Optical fibers are commonly used to provide aesthetically-pleasing lighting effects to highlight features and borders of buildings, landscapes, swimming pools, and the like. These exterior lighting installations typically require waterproof light sources that must be located close to the features or borders that are to be highlighted by light emitted from the optical fibers in order to preserve high intensity illumination over the length of the optical fibers. Lighting of this type commonly relies upon plastic optical fibers for low cost, flexibility, and immunity from weather conditions, but such fibers require significant cooling at the input ends in order to avoid melting and deterioration attributable to high-intensity light sources operated in close proximity to the fibers. Certain known light sources for exterior installations to provide light flux to optical fibers rely upon a pair of windows that are interposed between fiber ends and light source and that are spaced apart along the direction of illumination supplied to the ends of optical fibers in order to pass cooling air between the spaced windows (See, for example, U.S. Pat. No. 4,763,984). One disadvantage of light sources of this type is that the composite unit is unsightly and typically must be installed at substantial distance away from the features or borders that are to be lighted by the optical fibers which are illuminated by such light source.